NO138225B - HYDRAULIC RADIAL PISTON ENGINE OR PUMP - Google Patents

Description

The present invention relates to hydraulic radial piston motors or radial piston pumps which have a circular .'■

housing and in this a rotatably mounted cylinder block with a plurality of radial cylinder bores, each of which has a reciprocating piston, and with the housing's circular interior provided with a ■

fixed ring gear in that a gear fixed to a crankshaft for each of the pistons or on each pair of parallel pistons is in engagement with the ring gear, while the pistons are directly supported on an eccentric crank pin on the crankshaft.

In conventional hydraulic pumps or engines with radial pistons, it is common to use devices to increase the pressure of a. efficient flowing medium and/or increase the working volume of the flowing medium for each single revolution of the shaft to obtain a high output power with a small capacity. Attempts have been made to increase the diameter of the pistons or to increase the total piston stroke for each shaft revolution in order to

increase the working volume of the flowing ■medium for each shaft revolution. Such a case represents the total piston strokes of the pump or the motor, which can be obtained by multiplying the piston stroke by the number of pistons.

Examples of hydraulic motors or pumps of this type can be found in U.S. Patent Nos. 593,70 and 2,308,380. However, the construction of the known designs is very complicated.

sert, among other things, because the shafts for the various components are not concentric or flush with each other, but stand eccentrically. In the known pumps and motors, moreover, the radial pistons make only one reciprocating movement during one revolution, and to increase the working volume of the pump or motor'

increasing the diameter of the pistons also results in the pump or motor having larger external dimensions.

The purpose of the present invention is therefore to arrive at to a hydraulic radial piston engine or pump of the type described. the work volume is increased without the total ■ dimensions, measured externally, having to become larger. The construction "according to the invention is further such that the number of pistons can be increased, thereby achieving a significant increase in conveyed work volume per revolution.

According to the invention, this is achieved by a support ring being attached parallel to the ring gear around the inner circumference of the housing and the crankshaft being provided with a cam ring that rests against rollers along the support ring when the cylinder block rotates in relation to the housing.

Another feature is that the cam ring has an eccentric for,m and it can also be stored on the crankshaft with the help of a bearing.

In the following, the invention will be described in more detail with reference to the drawings in which: Fig. 1, seen from the side, shows a device according to the invention in section and from the front,

fig. 2 shows a part of fig. 1 in section and seen from the front,

fig. 3 shows a part of "fig. 1 on a larger scale,

fig. 4 shows a part of fig. 2 on a larger scale,

fig. 5 shows, seen from the side, a section of a part of another embodiment of the invention,

fig. 6-8 show, in graphic form, variations in the twisting moment that is obtained with the help of the pistons,

fig. 9 shows in a curve the variations in a piston stroke in a conventional device and

fig. 10 shows a curve for the variations in a piston stroke in an engine or pump according to the invention.

In fig. 1 is a main axis!.1 connected to a cylinder block 2 and prevented from rotating relative to the cylinder block by means of a track wedge device 25..A number of pistons 3 are inserted into the cylinder block 2 and arranged .radially relative to this. A pair of pistons 3, which lie side by side, are connected to a crank pin 8, which is made in one with a gear shaft 4. The gear shaft 4 has a center shaft '4' which is eccentric in relation to the crank pin 8's center shaft 8' (see fig. 4) . A gear wheel 5 is placed on each gear shaft 4. The gear wheel 5 is held in engagement

with an internally toothed wheel "9 which is attached to a housing.- -,<: >A plurality of chambers 6 (which in this embodiment are made in the form of rings) are located on opposite sides of the toothed wheel 5 (see fig. 3) and each one is arranged on the outer peripheral surface of each gear shaft 4. The cams 6 are arranged so that they move in a rolling motion on the inner peripheral surface of the auxiliary rings 7 which are-placed on opposite sides of the teeth...

" in the internal toothed wheel 9-

A rear cover 10 and a front cover 11 are clamped

against opposite side parts of the internally toothed wheel 9. The main shaft 1 is stored. in bearings.26 and 12 which are arranged respectively in the rear cover 10 and the front cover 11. Part of •

the front cover 11 through which the main shaft 1 passes is sealed with an oil seal 13•

The rear lid 10 is designed with outlet and intake openings 23 and 24 for the working medium...Whether these openings serve as outlet openings or intake openings varies i'

according to whether the device is used as a pump or motor. That. the rear lid 10 is further designed with annular channels 21

and 22 for the flowing medium and are held in connection with the outlet and intake openings 24 and 24, respectively, as well as the channels 21' and 22' before the flowing medium is delimited from the annular channels 21 and 22..•.'"' '"'-. V

A number of cylinder chambers 18, each of which contains an amount of flowing medium that acts on the piston 3, is

designed in the cylinder block-2. A number of channels 17 and 17' which extend from the cylinder chambers 18 along the central axis of the main shaft open into opposite side parts of the cylinder block 2, and a number of channels 19 which each simply connect each pair of cylinder chambers 18 which lie side by side about .side in.relation to each other, is also designed -in • the cylinder block 2.

Between the cylinder block 2 and the rear cover 10, a valve plate 14 is inserted which is designed with channels 15 and 16 so that the channels 15 are in connection with the channel 21' which is' designed in the rear cover 10,' and the channels 17 designed in the cylinder block 2, so that the channels 16 are kept in connection with the channel. 22' which is formed in the rear cover 10 and the channel 17 which is formed in the cylinder block 2- In the front cover 10 there are formed oil pockets 20 which are kept in connection with the channels 17'

which is designed in...cylinder block 2.

Fig-5 shows another embodiment of the invention where a number of pistons 29 are placed radially in a cylinder block 28.

Each individual piston 2 9 is connected with a crank pin 30 which is

•designed in one with.- a."'plural gear shafts '31 located "-. on opposite sides of the crank pin 30. Each individual crank pin 30

is eccentric in relation to the associated gear shafts 31. A plurality of rings 33 are placed on the gear shafts 31, via bearings 33' • The rings 33 are arranged so that they are moved in a rolling motion along the inside of the support rings 34 which are fixed by means of a cover 35. External gear 36, whose central axis line is in line with the main axis' central line, is designed in one piece with the lid 35 and is located in its protruding part. The gears 32 are held in engagement with the external gears 36.

The operation of the device according to the invention can be seen from the construction described above. The operation must be explained for a device that functions as a motor.

A working medium is supplied through the intake opening 23 and passes through the annular channel 21 and the channel 21' to reach one of the channels 15 in the valve plate 14 and then passes through one of the channels 17 in the cylinder block 2, so that it flows into one of the cylinder chambers 18 and sets one of the pistons in motion. At the same time, a part of the working medium passes through one of the channels 19 to the cylinder chamber 18 which lies side by side in relation to the first mentioned cylinder chamber 18, so that the adjacent piston 3 is set in motion..Part of . the working medium continues to pass through one of the channels 17 into the annular channel 20. The device according to the invention is constructed so that the pressure in a quantity of liquid which is introduced into one of the oil pockets 20 and the pressure in a quantity of liquid in the channels 15, balances so that all axial movement of the cylinder block 2 is avoided.

When the pressure of the working medium is applied to each of a pair of pistons 3 which lie side by side, the piston plane 3 is pushed outwards so that the crank pin 8 with which the piston pair 3 is connected is pushed radially in relation to the center of the engine. Because the crank pin 8 is eccentric with respect to the gear shaft 4, a force acting on the crank pin 8 acts as a rotational force that twists

the crankshaft 4 about its own central axis "4'". The gear wheel 5 rotates

about its own center axis when the pinion shaft rotates so that the pinion is moved in a rolling motion while it is held in engagement with the internally toothed wheel 9.

Rolling movement .or rotation of the gear wheel 5 about - .its own center axis causes the associated pair of pistons 3 to be moved in a reciprocating motion in the cylinder block,

which in turn is caused to rotate relative to the internally toothed wheel 9- The path of movement of the center shaft 8' on

a particular crank pin -8 can be expressed as a curve 27, shown at

fig. 2. If the internally toothed wheel 9 is fixed so that it cannot move, the rotation of the gears 5 about their own axes causes the cylinder block 2 to rotate about the main shaft 1 and thereby causes the main shaft 1 to rotate via the spline device 25. The main shaft i thus functions as a drive shaft.

With this business, the number of revolutions for a

given gear 5 about its "own center axis for each complete revolution of the main shaft 1, is expressed by means of the formula

m = D/d

where D is the diameter in the segment circle of the internally toothed wheel 9 and d is the diameter in the segment circle of the toothed wheel 5. Each stamp

3 thus moves in a reciprocating motion m

times for each complete revolution of the main shaft 1, so that the volume of. the working medium in the engine for each revolution of the main shaft can be increased to a high degree. Fig. 2 shows a case where m is equal to 8.

The valve plate 4 is constructed and arranged in such a way that the cylinder chamber 18 is connected to the pistons 3 which are in the position in which they are pushed or moved outwards in relation to the cylinder block -2. the working medium which through the channel 15 is connected to the channel 21' on the high-pressure side, and that the cylinder chambers 18 are connected to the pistons 3 which are in the position in which they are pushed or moved into the cylinder. the block 2 of the working medium which, via the channels 16, is in connection with the channels 22' on the low pressure side or the discharge side.

If the cams 6 which are placed on the gears and the shafts have an outer diameter equal to the diameter of the gears 5

-■ pitch circle, the gears are moved in a rolling motion while they are held in engagement with the 'internally toothed wheel 9, so that

control occurs between the cams 6 and the auxiliary rings 7 because the cams 6 move in a rolling motion along the inner peripheral surfaces of the hinges 7, through which the cams 6 are held in rolling contact, with the auxiliary rings 7. Consequently, a component of the force exerted by the associated pistons 3 which are directed radially in relation to the gear shaft is taken up by the part of the internal toothed wheel 9 in which the associated toothed wheel 5 engages besides the contact points of the cams 6 with the auxiliary rings 7 - The devices according to the invention are thus designed to work with a working medium with high pressure. In addition, the device can withstand operation with a high number of revolutions

due to the fact that the centrifugal force caused by the gears 5 is taken up by the associated auxiliary rings 7-

In the first described embodiment, slippage between the cams 6 and the associated auxiliary rings 7 is prevented during operation by the engagement between the gears 5 and the internally toothed wheel 9. It is understood that if you use surfaces with high frictional resistance that do not cause slippage between the cams 6 and the auxiliary rings 7, the gears can be dispensed with.

Although the invention is shown and described in connection with embodiments in which the device according to the invention is used as a motor, it is clear that the device can also be used as a pump if the above-described mode of operation is reversed in the same way as for normal motors and pumps for streaming media. Further explanations of the operation of the device such as a pump are therefore omitted. When the device according to the invention is used as a pump, the piston 3 is moved in a reciprocating motion m times during one complete revolution of the main shaft before the flowing medium is discharged.

A spring may be provided in each piston for relief

the movement of the pistons during the pump's suction stroke.

In the second embodiment shown in fig. 5, the gear wheel 32 is held in engagement with the outer ones; toothed wheels 36 in opposition to the gears held in engagement with the internally toothed wheel 9 in the first embodiment. Accordingly, the cams or roller rings 33 are moved in a rolling motion along the inside of the auxiliary rings 34. Because the crank pin 30 is eccentric in relation to the gear shafts 31, the piston 29 can be held in a reciprocating

walking movement.

- The cams 6, which in the embodiments are intended to be held in contact with the auxiliary rings 7, are explained in connection with an example in which the cams 6 are made in the form of eccentric rings.

However, it is understood that any desired

shape can be chosen for the combs 6 as long as the shape meets the properties required for a device for flowing media..

Fig. 6A shows the relationship between the twisting angle 0 of the main shaft 1 and the twisting moments produced by the pistons (which is made up of the - calculated torque as this is a pump and in what follows is calculated as produced torque). when the cams 6 consist of eccentric rings or eccentric cams. ; The twisting angle of the main shaft is set along the abscissa axis and the produced twisting moments along the ordinate axis. It appears from a piston (which can be called the first piston) produces a torque which can be represented by a sine curve which is obtained by connecting the points 40, 43

and 41 and that another piston, (which is a piston that works second after the first piston in chronological order, and which does not necessarily have to be at a point close to the first piston) produces a torque which can be represented by a sine curve which is obtained by connecting points 42, 44 and 45. If a stamp no. 3 and the subsequent stamps are set in turn in "movement", get. the engine that has these stamps a torque that can be represented by a combined

set curve which can be designed by connecting the points 46, 47 and 48, 49 as shown in fig. 6B, which is obtained by combining the sine curves representing the torques produced by all the pistons. It also appears that this composite curve has highly elevated parts and deeply depressed parts which indicate that the torques produced are subject to large changes in size.

It has been found that if the chambers 6 are made with a suitable shape, such as an egg shape and not as eccentric rings as mentioned above, the pistons produce a torque which can be represented by the trapezoidal curves shown in Fig. 6C, and that the torque produced by - all the pistons- can be represented by a straight line where the trapezoidal curves representing the torques produced by all the pistons are combined into a composite curve showing that there is no

.. change in the magnitude of the torque that is produced

of all the stamps. - As shown in fig. 6C, a first piston produces a torque '-' which can be represented by a curve obtained by connecting points 50, 52, 53 and 51, and a second piston produces a torque which can be represented by a curve obtained by. to connect points 54, 56, 57' and 55- It appears that part of the torque produced by the first piston between points 52 and 53 and part of the torque produced by the second piston between points 56 and 57" is equally and that the time interval during which the torque produced by the first piston and the second piston between the points 53 and 51 and the points 54 and 56, respectively, overlaps.

If the starting point 53 of the reduction of the torque produced by the first piston and the starting point 54 of the production of the torque produced by the second piston are made to occur at the same time and if the delay point 51 of the torque produced by the first piston and the termination point 56 of the increase of the torque produced by the second piston is made to occur at the same time so that the sum of the torque produced by the first piston and the torque produced by the second piston at the same time can be constant in all cases and the sum of the torque produced by the first piston and the torque produced by the second piston at another point is constant for all cases, a curve representing the composite torque obtained by combine the torque produced by the first ste mpel and the torque produced by the second piston, of a straight line, as shown in fig. 6D, indicating that there is no change in the magnitude of the twisting torque produced by the piston.

To make the sum of the torque produced by the first piston and the torque produced by the second piston at a corresponding point equal to the sum of the torque produced by the first piston and the torque produced by the second piston in another . time, for all cases mentioned above, the sum of the torque 83 and 81 produced by the first piston and the torque 83 and 82 produced by the second piston shown in fig. 6, constant in all cases.

In this description, it is assumed that a plurality of pistons which are in relation to each other, in the torque produced by them, are in a corrected relationship.

Fig. 6E shows an example in which the torque as

is produced by the pistons, is subject to variations that can be expressed linearly. In this case, the changes in the torque produced by the piston are therefore defined so that the composite curve of the produced torques can be shown as a straight line, which in this case is shown in Fig. 6C.

If the time interval 60, 6-4 (corresponding to the distance between points 60 and 64) during which the second piston lags behind the first piston during the movement is half the time interval 60-6l (corresponding to the distance between points 60 and 6l) , it is possible to bring them. first and second stamps in"

a corrected ratio if the torque produced --■ , by the first and second pistons is not made to undergo varia-

tions which are triangular in shape," as shown in Fig. 7.

Although the embodiments shown and described above apply

a case in which two pistons are brought into a corrected relationship with respect to the torques produced by them, it is understood that it is "also possible" to bring more than two pistons into a corrected relationship to a piston with respect to changes in the torque produced of them This embodiment is

. shown in fig. 8A and 8B.

In fig. 8B, the changes in torque produced by the first piston are expressed by a curve constructed by connecting points 91, 93, 94 and 92, the changes in torque produced by the second, a curve constructed by connecting points 95, 96, 93 and 97* changes in the torque produced by the third curve of a -curve constructed by connecting 98, 99 and 100, changes in the torque produced by the fourth piston by: using a - curve - which is constructed by connecting

... xispjunkten^I,Ql,':T0-2, 99, 103, and changes in the torque somje-r*;T remb rakt.'ra v det., fifth piston" by means of a curve like """ --. ei-ciconstructed. -by-connecting points 104, 1C5, 102 'and 106. I

in this case, the "first piston" is located in the first half of the corrected torque curve in corrected relation to the third, fourth, and fifth pistons. More precisely, the sums of the value 91 -93- and- the values' 96-100, 99-103 and 102-106 in

.-every .-point -i. time or • at the same angle of twist constant, ~v1s"like::'as, shown in Fig. 8B. In the second "half" of the' constructed "rioxriding moment curve for' the first piston is located - the pistons - show changes that are represented of the lines 103-107, 100, 108-^and 97-109 in-a corrected 'relation-to-the first -stamp which is represented' by the line 94-92,- slack that the sums1 of the values itsetthwhatever" any point in time is" constant, as shown on-^fig; 8b.- S

rtStosw-Out from 'the above it appears that/the stamps can be brought into:5nse<k>t'r-.corrected relationship with each other even if the first half and

the;-other half of the waveform in one curve representing

The torques produced by the pistons are not symmetrical

Fig. 9 shows the relationship between the twist angle 9 for

• "the main axis 1 and the stroke S of a piston in a case where the cam-Mrigs 6 are eccentric rings. In the figure, the angle of rotation 6' of the rotation axis is laid out along the abscissa axis "and the piston sig" S

'i2?ång-s"ordinate axis. A certain stamp (which^can

piston)■ moves in a piston stroke which is represented'"■'by one

■'."sine curve which is constructed by connecting the points- 120j 121, 122 and 123- In this case, the points 121 and 123 constitute the top dead-i^ points' and the point 22-constitutes the bottom dead center -in the .piston mcflage ". The points 124, 125 6g,<:>'126 are points in which the channel-17

until the cylinder chambers 18 are shut off from the connection with one of the channels 15 for connection with one of the channels 16, or vice versa.

«V-.<:>Me-r precisely speaking, the piston is moved during operation, with force

<9>irSftover from •'•the upper dead center to a lower dead center-" between " point-*G-'en&°12'4 ©g' 12-5, so that the working medium in the cylinder chambers 18 flows out through one of the channels 16 .The piston moves in operation with the force out from the bottom dead center to the middle dead center

points 125 and 126 so that the drive medium is supplied. cylinder cam

moret 18 through one of the channels 15..

In such a case, the piston operation cannot be carried out synchronously with the correct switching of the cylinder chambers between the

the connection with one type of channel in the valve plate 14 and the connection with the other type. channel therein, and the piston movement can serve no useful purpose. unless the top dead center 121, the bottom dead center 122 and the top dead center 123 are made to coincide completely with the respective switching points 124,

125 and 126. Moreover, if this conformity cannot be observed, the liquid which is intended to be released is confined in

the cylinder chambers and thereby cause waves and pulses

inger. For this reason the tolerances are very small and exact machining and assembly of the parts is required in order for the top and bottom dead centers to completely coincide with the switching points.

The present invention avoids the above-mentioned problems

in that in the vicinity of the top and bottom dead centers for piston

lene's operation is arranged in sections in which the piston stroke is equal to zero. In fig. 10, the piston follows a curve which is constructed by connecting the points 127, 134, 128, 135, 136, 129, 137, 138, 130 and 139. The points 128 and 130 form the top dead center and the point 129 forms the bottom dead center,- and items 131, 132 and 133

form points in which the switching between the channels of the valve plate takes place. The sections in which the speed of the piston stroke is zero are formed between points 134 and 135 with the top dead center 129 lying in the middle point between the points 136 and 137 and with the bottom dead center 130 lying in the middle and between 138' and 139, with the

top dead center 130 lying in the middle.. •■ ;

The piston operation can be carried out as planned to achieve the desired results if the deviations of the -upper and lower dead center from the coincidence with the switching points are within the range for each and every one of these sections. Moreover, it can be unnecessary

piston movement and the appearance of waves and vibrations are avoided

be avoided.

The device with sections in the vicinity of. the top and bottom dead centers of the piston movement in which the piston stroke is zero, • can be easily provided by means of a suitable design

the shape of the cams 6 which are intended to come into contact with

the auxiliary rings 7 in a manner known in the processing technique.

From the description above, it appears that the invention makes it possible to obtain a device for flowing. media that are simple in construction and easy to manufacture due to the fact that tight tolerances are not required, and which can be used as a pump or

motor for handling ..of efc .flowing medium with high pressure and with high speed.

It is clear that although the first shown and described

■ device works in such a way that the main shaft can be connected to a driven shaft or a drive shaft and the Internal toothed wheel is fixed so that it cannot move, the main shaft can be fixed so that it cannot move and the internal toothed . the wheel be connected with a. driven shaft or drive shaft...,.

The use of gears according to the invention • makes it possible to obtain a device for a flowing medium which is less complicated in construction and easier to manufacture than conventional devices in which the pistons are designed so that they move in a sliding motion on a "complicated curve surface.

Claims (3)

1. Hydraulic radial piston engineJeller pump with a 1. a circular housing (10, 11) rotatably supported cylinder block (2) having a plurality of radial cylinder bores with reciprocating pistons (3, 29) therein, with the circular inside of the housing equipped with a fixed ring gear (9, 36), in that a gear (5, 32) fixed to a crankshaft (4, 31) for each of the pistons (29) or for each pair of parallel pistons (3) is in engagement with the ring gear (9, 36), while the pistons (3 , 39.) is directly supported on an eccentric crank pin (8, 30) on the crankshaft (4, 31), characterized in that a support ring (7, 34) is attached parallel to the ring gear (9, 36) around the housing (10, 11) inner circumference and that the crankshaft (4, 31) is provided with a cam ring (6, 33) which rests against and rolls along the support ring (7j 34) when the cylinder block (2) rotates in relation to the housing (10, 11). 2. Hydraulic radial piston motor or pump as specified in claim 1, characterized in that the cam ring (6.333 has an eccentric shape. 3. Hydraulic radial piston motor or pump as specified in claim 1 or 2, characterized in that the cam ring (33) is supported on the crankshaft (31) by means of a bearing (33')•